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Biomedical subjects

A M Courouce

Publications and source records attributed to A M Courouce.

At least 55 records · Page 3Linked to original sources
PubMed1987

Antibodies to synthetic peptides from the pre-S1 and pre-S2 regions of one subtype of the hepatitis B virus (HBV) envelope protein recognize all HBV subtypes.

Immunodominant B and T cell epitopes have been demonstrated recently on the preS1 and PreS2 regions of the hepatitis B virus (HBV) envelope protein. Synthetic peptide analogs corresponding to the preS2 region elicit virus-neutralizing antibodies and protect chimpanzees against HBV infection. Antibodies raised by immunization with peptides derived from the preS1 sequence block the site involved in HBV attachment to cell receptors, and are expected to be virus-neutralizing. Results presented here show that antisera raised against synthetic peptide analogs carrying the immunodominant epitope of the preS1 and preS2 sequence, respectively, and corresponding to two HBV subtypes, adw2 and ayw, each recognized preS1 and preS2 specific epitopes on all serological subtypes of the HBV envelope protein. Thus, the sequence variability within the preS1 and preS2 regions does not represent an impediment to the development of synthetic peptide or genetically engineered hepatitis B preS immunogens for worldwide immunization.

Amino Acid Sequence↗
PubMed1987

Non-radioactive hepatitis B virus DNA probe for detection of HBV-DNA in serum.

A diagnostic test has been developed to detect hepatitis B virus (HBV) DNA in human sera. This test involves a dot-blot technique in which non-radioactive nucleic acid labelled with 2-acetylaminofluorene (AAF) is used as probe. Two series of human sera from 228 blood donors and 113 HBsAg chronic carriers were tested by hybridization with the same DNA probe labelled either with AAF or with 32P. A correlation between the techniques was observed for 328 sera (96%), and using the non-radioactive test it was possible to detect 56 (86%) of the 65 HBV-DNA-positive patients. A comparative study of the HBeAg/anti-HBe status and the presence of HBV-DNA was carried out on the sera from 113 HBsAg chronic carriers, 65 of which were positive for HBeAg and 29 of which were positive for anti-HBe antibodies. With the AAF test, 44 of the HBeAg-positive sera were positive, while 5 of the anti-HBe-positive sera were positive. This study shows that, although this non-radioactive test is slightly less sensitive than the radioactive hybridization assay (RHA), it can be used for a survey of HBV carriers. Dissociation of the viral multiplication and the HBe/anti-HBe status was identified with the AAF test as well as with the RHA. It would therefore appear that the AAF test described here may be used for the extensive survey of HBV multiplication.

2-Acetylaminofluorene↗
PubMed1986

[Hepatitis B virus DNA as a marker of viral multiplication: comparison with HBe antigen and anti-HBe antibody].

We have used D A-DNA hybridization techniques with a spot test procedure for the detection of hepatitis B virus (HBV) DNA in the serum of 156 HBsAg positive patients with chronic active hepatitis and 75 asymptomatic chronic carriers of the virus. The results were compared with those of HBeAg and anti HBe tests. HBV DNA was detected in the serum of 107 of the 132 (81%) HBeAg positive and 6 of the 24 (25%) anti HBe positive patients with chronic hepatitis. A semi-quantitative estimation of the amount of viral particles showed a marked heterogeneity among the positive sera. HBV DNA was not detected in the serum of 25 patients despite HBeAg positivity: serial samples were available for 13 of these subjects and HBe became undetectable in 9 cases after 6 to 12 months. Among the 75 anti HBe positives asymptomatic carriers HBV DNA was detected in 3 (4%). It appears that HBV DNA detection in the serum is a much more sensitive and direct assay for HBV multiplication than the HBeAg and anti HBe tests.

Carrier State↗
PubMed1986

[Parvovirus B 19].

Since 1981, many reports have contributed to establish that a human parvovirus (parvovirus B 19), which had been isolated only in asymptomatic blood donors, is the causative agent of transient but intense erythroblastopenia in patients with different types of chronic haemolytic anaemia. In vitro cultures of erythroid inhibitors revealed an inhibition by parvovirus B 19, abolished by convalescent serum. In healthy subjects without chronic haemolysis, first contact with parvovirus B 19 results in an inconstant influenza-like syndrome with transient erythroblastopenia which does not produce symptoms since the normal erythrocyte life span covers the effect of parvovirus B 19 on bone marrow. Parvovirus B 19 is also suspected to be the causative agent of erythema infectiosum (fifth disease) which occurs in children.

Anemia, Aplastic↗